\documentclass{standalone}


    % GRAPHICS
\usepackage{tikz}
\usepackage{pgfplots}
\pgfplotsset{width=7cm,compat=1.3}

\definecolor{blue}{RGB}{0,105,168}
\definecolor{lightblue}{RGB}{0,180,255}
\definecolor{red}{RGB}{217,88,160}
\pgfplotsset{grid style={dashed}}
\begin{document}

\begin{tikzpicture}

\begin{axis}[
	tick label style={/pgf/number format/fixed},
	scaled ticks=false,
  grid=major,
  ymin=-30, ymax=10.0,
	xtick={-7.5e6,-5e6,-2.5e6,0,2.5e6,5e6,7.5e6},
	xticklabels={-7.5,-5,-2.5,0,2.5,5,7.5},
	xmin=-7.5e6,xmax=7.5e6,
  xlabel={Frequency [MHz]},
  ylabel={Magnitude [dB]},
]

    \addplot[color=blue,line width=1.3pt]
	table [col sep=space]
	{data/spectrum_without.txt};




\end{axis}


\end{tikzpicture}
\end{document}